This invention relates to an electronic device with an electroluminescent panel.
Electronic devices which have a display section and a key operation section with a plurality of keys (operation switches) include a cellular phone, an electronic calculator, a liquid crystal TV, a radio with a display capable of receiving a teletext multi-plex broadcast, etc. Some of the electronic devices have a structure in which a light emitting diode (LED) is arranged on the rear surface of a transparent operation panel. This LED illuminates the key operation section through the panel to facilitate the key operation even in a dark place.
Since in the conventional electronic devices, the LED performs point emission, only that portion and its vicinity of the panel, at which the diode is mounted, is illuminated. This means that the keys have different brightnesses and hence do not have a good appearance. Moreover, since the LED is attached to the circuit board by soldering, the attached portion becomes locally thick. This is inconvenient for realizing a thin assembly. In addition, when the display section comprises, for example, a liquid crystal display panel which requires a light source, light sources are necessary for both the key operation section and the display section. As a result, the wiring and the mounting structure of the electronic device become complicated, which is a serious obstacle in developing more compact electronic devices.
It is an object of the invention to provide an electronic device having a simplified mounting structure equipped with a display section and an operation section which both require illumination, to thereby reduce the size of the electronic device.
To attain the object, there is provided an electroluminescent panel-attached electronic device comprising: a display panel for controlling transmission of incident light from an outside to perform display; operation panel having an operation switch and capable of substantially transmitting light through at least a portion thereof which requires illumination; and a single electroluminescent panel (hereinafter referred to as xe2x80x9cEL panelxe2x80x9d) provided on a rear surface of each of the display panel and the operation panel for illuminating the display panel and the operation panel.
Since in the above EL-attached electronic device, the display panel and the operation panel can be illuminated by a single thin EL panel, the electronic device with the display panel and the operation panel can have a simple mounting structure and hence a much more compact size.
Preferably, in the EL panel-attached electronic device, the substantially overall rear surface of the display panel is adhered to the EL panel by an adhesive. As a result, the vibration sound generated from the EL panel can be reduced. Further, the emission color of the EL panel can be adjusted by diffusing a pigment into the adhesive.
More preferably, the EL panel-attached electronic device further comprises a flexible circuit board electrically connected to the display panel and the operation panel, and the flexible circuit board is adhered to a rear surface of the EL panel by an adhesive. In this case, it is also preferable that the EL panel is flexible. As a result, an electronic device is obtained in which the display panel section can be folded on the operation panel section.
Further, the EL panel may have an electroluminescent layer herein after referred to xe2x80x9cEL layerxe2x80x9d formed by diffusing fluorescent material powder into a dielectric layer, and a pair of electrodes holding therebetween the EL layer, and the EL layer may be selectively formed on the display panel and the operation switch.
Also preferably, in the EL panel-attached electronic device, the display panel is a liquid crystal display panel which includes a pair of substrates, each having electrodes and liquid crystal sealed therebetween. In this case, it is also preferable that the pair of substrates of the liquid crystal display panel are flexible electrode substrates obtained by forming electrodes on flexible films.
Further preferably, in the EL panel-attached electronic device, the EL panel has an EL layer formed by diffusing fluorescent material powder into a dielectric layer, and a pair of substrates holding therebetween the EL layer, at least one of the substrates which faces the operation panel being transparent, the substrates having electrodes formed on opposed surfaces thereof, a color adjusting layer for transmitting therethrough light of a desired wavelength being selectively formed on a predetermined portion of a front surface or a rear surface of the transparent at least one of the substrates. As a result, multi-color illumination can be performed.
In addition, the structure of the EL panel-attached electronic device is applicable to a cellular phone.
Another object of the invention is to simplify the assembled structure of an electronic device equipped with a liquid crystal display panel and another display section which both require illumination, to thereby reduce the size of the electronic device.
To attain this object, there is provided an EL panel-attached electronic device comprising: an EL panel having an EL layer held between a pair of substrates which have electrodes formed on opposed surfaces thereof; a liquid crystal display panel provided on a predetermined surface portion of the EL panel, having liquid crystal sealed between the substrates, each provided with an electrode, and capable of controlling the transmission of light by changing orientation of liquid crystal molecules; and an EL display section formed on a surface portion of the EL panel other than the predetermined surface portion, the electroluminescent display section performing display by light emitted from the electroluminescent panel.
Since in the above EL-attached electronic device, the liquid crystal display panel and another display section can be illuminated by a single thin EL panel, the electronic device with a plurality of display sections including the liquid crystal display panel can have a simple mounting structure and hence a much more compact size.
Yet another object of the invention is to provide a compact electronic device including an operation panel with a plurality of operation switches which can be uniformly illuminated in a dark place.
To attain the object, there is provided an EL panel-attached electronic device comprising: an operation panel having a plurality of operation switches and substantially transmitting light through at least a portion thereof which requires illumination; and an EL panel provided on a rear surface of the operation panel and formed by holding an EL layer between a pair of substrates which have electrodes formed on opposed surfaces thereof, at least one of the substrates which is positioned on the side of the operation panel being transparent.
Since in the above EL panel-attached electronic device, the EL panel uniformly illuminates the substantially overall rear surface of the operation panel, all operation switches can be uniformly illuminated and therefore easily operated in a dark place.
In the above-described El panel-attached electronic device, it is preferable to selectively provide a color adjusting layer for transmitting therethrough light of a desired wavelength, on a predetermined portion of a front surface or a rear surface of the transparent at least one of the substrates. As a result, the operation switches of the operation panel can be illuminated with light of any desired color, which enhances the commercial value of the electronic device.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The object and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.